Liquid fuel furnace



March 7, 1939.. s, H HOOK 2,149,770 LIQUID FUEL FURNACE: I

Filed Feb. '7, 1938` 2 Sheets-Sheet O v(DOOOOOOO Patented Mar. 7, 1939LIQUID FUEL FURNACE Sydney Harold Hook, Gardiner. victoria,l AustraliaApplication February 7, 1938, Serial No. 189,265 In Australia April 22,1936 '7r Claims.

This invention relates to liquid fuel furnacesV to provide an improvedliquid fuel furnace of thel l type indicated which embodies improvedmeans for dividing the film of fuel flowing over the burner plate andthe air draft passing thereover, into a large number of relatively smallstreams thereby ensuring an intimate mixing of the air and fuel vapourand a material improvement in the general efficiency of this type offurnace.

Another object of the invention is to provide in a liquid fuel furnaceof the type referred to, improved draft control means whereby one or 20;more'induced airdrafts is or are directed downwardly towards the burnerplate and caused to pass over the inner end portion thereof in closeproximity to the film of liquid fuel owing there- A over; whereby mixingof the air and fuel vapour 25' and combustion of the resultant gases isgreatly improved while the possibility of the ignited gases blowing backtowards the front of the furnace, is reduced tofa minimum.

Referring to the drawings which form part of I 3U* this specification:-

Figure 1 is a longitudinal section of an improved liquid fuel furnace inaccordance with one embodiment of the present invention.

v Figure 2 is a part-sectional plan View taken on the line II-II ofFigure 1. Figure 3 is a fragmentary section onan enlarged scale of theinner edge portion of a burner plate in accordance with a modificationof the invention.

` Figure 4 is a fragmentary plan view of the burner plate seen in Figure3.

Figure 5 is a front view of the furnace seen in Figure 1, parts beingbroken away for convenience of illustration. Y

Figure 6 is a cross-section taken on the line VIV- VI of Figure 1.

`Figure 7 is a fragmentary plan View on an enlarged scale showing meansfor delivering a plurality of relatively small streamsY of water ontheburner plate.

Figure Sis a fragmentary longitudinal section of the lower end portionof a burner plate in accordance with a' further modification of the in.-

,65 Yention. v Y

Figure 9 is a cross-section taken on the line IX-IX of Figure 8.

In accordance with one practical embodiment of the invention asillustrated in Figures 1, 2, 5 and 6 of theA drawings, the improvedliquid fuel furnace includes a burner plate 2 mounted upon a supportingframe 3 and inclined downwardly from the front towards the rear so as tocause oil or like fuel which is deliver-ed onto the upper surface oftheburner plate to gravitate in a relativelythin lmtowards the inner edgethereof, as Ahereinafterdescribed.

This burner plate 2 preferably includes a main fiat section 4 providedat its inner end with one or more stepped portions E which are locatedat a lower level than that of the main section. As illustrated in Figure1 of. the drawings, two of these stepped portions may be employed andthe upper surface 'l of each stepped portion is preferably inclined inthe opposite direction to that of the mainV section 4 of the burnerplate with a view to trapping the residue of the liquid fuel owing overthe lower edge of the main section of the burner plate until the fuel isfinally consumed.

. Alternatively, if two of such stepped portions areemployed, the upperone 6a may be inclined in the same direction as that of the main section4 of lthe burner plate, while the lower stepped portion 6b is inclinedin the opposite direction as seen more clearly in Figure 3 of thedrawings.

Each stepped portion 6 of the burner plate also includes an upright wall8 provided with a plurality of longitudinally spaced apertures 9 formedtherethrough in order that a draft of air may be induced to pass throughthe fuel falling downwardly lacross said apertures. Provision is alsopreferably made for directing a draft of air beneath the lowermoststepped portion of the burner vplate and for this purpose the latterstepped portion may be provided with a plurality of depending lugs IIadapted to rest upon a tray or-bottom wall I2 of the furnace, thusforming air passages between said lugs.

Y .Liquid fuel is fed by gravity, for example from ajsuitable container(not shown) through one orimoredelivery pipes I3 into a well or recessI4 formed in the upper surface of the main section 4 of the burnerplate. This well may be circular, elongated or any other suitable shapein plan and one or more of such wells may be employed depending upon`the width of the burner plate.V Eachsuch well I4 communicates with aseries of open-ended channels I6 which are formed in the uppersurface.of the burner plate and radiate towards the lower inner edge thereof. YThese channels may progressively decrease in depth as they approach theinner edge of the burner plate. Each of these channels may also increasein width as it approaches its lower end, so that the liquid fuel isspread over the burner plate and caused to flow towards the inner endthereof in a relatively thin film.

The main section 4 of the burner plate is provided adjacent the lower orinner end thereof with means for dividing the lm of oil or like fuelpassing over this section of the burner plate into a large number ofrelatively small streams. For this purpose, the burner plate is providedwith a series of upstanding and laterally spaced projections i8 whichare preferably arranged in one or more rows extending completely acrossthe burner plate adjacent to the rear or inner edge of the main section4 thereof. Each such projection is of substantially pear-shape in plan,the front edge portion of the projection being relatively wider than therear edge thereof. For eX- ample, the front edge I9 may be ofsubstantially convex curvature and merge into side walls 2l which taperinto a relatively thin tail 22 at the rear of the projection. Suchtapered projections have proved to be particularly ecient in effectivelydividing the oil or like fuel into a num ber of small streams. Y

If more than one row of such spaced projections I8 are employed, theprojections in adjacent rows are preferably staggered in such a mannerthat the tails 22 of the projections in the front row are located inalignment with the spaces between the projections in the rear row asseen more clearly in Figure 6 of the drawings.

A continuous or unbroken rib 23 preferably eX- tends across the burnerplate Ybetween the series of upstanding projections I8 and the inneredge of the main plate section Il. 'I'his rib is adapted to function asa dam for retarding the escape of the liquid fuel over the inner edge ofthe main plate section.

If desired, the inner edge portion of the main section of the burnerplate may overhang the upright wall 8 of the associated stepped portionas at 26 so as to induce the liquid fuel to fall freely from the outeredge of such overhanging portion instead of creeping down the rear faceof the upright wall. If more than. one stepped portion 6 is employed,the rear edge of the uppermost stepped portion may overhang the uprightwall 8 of the next stepped portion as at 21.

In combination with the foregoing, means is provided for inducing one ormore air drafts to pass downwardly towards and over the upper surface ofthe main section of the burner plate in close proximity to the liquidfuel flowing thereover. For this purpose, one or more hoods is or aremounted above the burner plate and one of these hoods 3l communicateswith one or more inlet openings 32 in the supporting frame 3. Theseinlet openings may be arranged one above the other as shown and each ofthese openings is tted with an adjustable closure for the purpose ofVarying the effective area thereof in accordance with requirements. Suchclosures preferably consistof hinged doors 33 as seen more clearly inFigure 1 of the drawings. These doors are provided with handles 34 andretaining means for holding them in the desired positions.

The hood or deflector 3l extends downwardly and rearwardly across themain section 4 of the burner plate and the lower or rear edge 36 of thishood is, in the embodiment illustrated in Figure 1, located in closeproximity tothe upstanding projections I8 thus forming a restricteddischarge opening which is interrupted by the series of projections. Thelatter are thus adapted to perform the additional function of bafflingthe air drafts. This hood 3l is also preferably provided with a seriesof apertures 3l adjacent to the top thereof in order to by-pass part ofthe air draft and thus obviate the formation of soot upon the rearsurface of the hood. Another series of apertures 38 may also be formedin the supporting frame 3 immediately above the hood 3| for a similarpurpose.

The position of the lower edge 36 of the hood 3l in relation to theseries of upstanding projections IB may vary in order to increase orreduce the effective area of the discharge opening for the air draft inaccordance with requirements. For example, the velocity of the airdrafts may be reduced by increasing the height of the discharge openingor by positioning the lower edge 33 of the hood either forwardly Aorrearwardly of said projections.

In View of the fact that the liquid fuel and the combustible gases areintended to be ignited at the rear of the series of upstandingprojections I8 on the burner plate, it is preferred to locate the loweredge 36 of the hood in relatively close proximity to the top of theprojections I8 as shown, in order to minimize the possibility of theignited gases being blown back under the hood and thus igniting the fuelon the burner plate in front of the projections.

Should it be desired to still further increase the air draft, anauxiliary hood 39 may be positioned at the rear of the hood 3| andcommunicates at its upper end with another aperture in the frame 3fitted with an adjustable closure. This auxiliary hood extendsdownwardly over the stepped portions 6 of the burner plate 2 asindieated for example in Figure l and. thus functions to direct theignited gases downwardly towards the inner end portion of the burnerplate thus increasing the temperature of the latter and tending toensure complete combustion of the gaseous fuel.

The interior of the hood is preferably divided by one or more partitionsor deectors 4I in order to direct the air draft downwardly towardsdifferent areas of the burner plate. In the embcdiment illustrated inFigure I of the drawings, a vfunnel 42 is preferably provided at thefront of the burner plate in order to direct a draft of air straightacross the latter towards the series of projections I8 in closeproximity to the surface of the fuel flowing over the burner plate. Thisfunnel is preferably open-ended and devoid of any adjustable closure. f

As Vpreviously mentioned, it is also desirable to cause an air draft topass through the apertures 3 in the stepped portions 6 of the burnerplate and also beneath the lowerrnost stepped portion. An air passagemay be formed between the bottom ofthe burner plate, the tray i2 at thebottom of the furnace-and walls 46 upstanding at the top of the burnerplate 2 and associated hood or hoods 3| as indicated in Figure 1.

In order to still further improve the caloric value of the furnace gasesa relatively small quantity of water may be fed onto the burner plate.This water rapidly vaporizes upon reaching the hot burner plate and theconstituent gases of the water are entrained in the air draft and mixedwith the combustible gaseous mixture within the furnace. This water maybe delivered to the burner plate 2 at several spaced points inrelatively small streams. For this purpose, a distribution cup I may beprovided for receiving water from a main water supply pipe 52 and thiscup communicates with a series of spaced delivery pipes 53 extendingdownwardly towards the surface of the burner plate. The cup is providedwith a plurality of internal baffles 54 adapted to split the stream ofwater received from the main supply pipe into a series of small streamswhich are directed to the respective delivery pipes. Or if desired, thewater may be introduced into the delivery pipe I3 for the liquid fueland discharged therewith onto the burner plate.

According to a modification as illustrated in Figures 3 and 4 of thedrawings, a single row of upstanding spaced projections I8 on the burnerplate is provided. This row of projections is positioned between therear edge of the burner plate which is serrated as at 56 and a rib 51which extends transversely of th'e burner plate in advance of suchprojections and is divided at klongitudinally spaced points so as toform openings 58 through which the liquid fuel is permitted to pass tothe row of projections. This rib 51 also functions as a dam so as toretard the escape of the fuel over the lower end of the burner plate,thus retaining it as long as possible upon that part of the plate whichis at the highest temperature and facilitating the vaporization of thefuel.

According to a still further modification as illustrated in Figures 8and 9, the upstanding projections upon the upper surface of the burnerplate 2 form part of a plurality of plates 6I which are spaced apart bysupporting bars 62 and extend transversely of the burner plate. Each ofthese plates is provided with a series of longitudinally spacedapertures 63 forming projections Ia therebetween. As seen in Figure 9,each of these projections is tapered downwardly towards its lower end soas to divide the oil or like fuel flowing across the burner plate intorelatively small streams. The projections in the associated plates arestaggered in order to'improve the division of the fuel as aforesaid.

If desired, a burner 66 adapted to be supplied with oil or like fuel forexample, from the aforesaid liquid fuel container, may be positionedbeneath the burner plate 2 in order to increase the temperature thereofand thus facilitate vaporization of the liquid fuel.

In use, oil or like fuel is fed onto the burner plate 2 and caused toflow downwardly thereover in the form of a relatively` thin film untilit strikes the series of upstanding projections I8 which divide the fuelinto a large number of relatively small streams. The fuel is ignited atthe rear of the projections I8 in any suitable manner such as byemploying a wad of inflammable cotton waste or the like. The air draftspassing through the furnace both above and below the burner plate 2 maybe readily controlled simply by adjusting the aforesaid closures 33, 4lassociated with the air inlet apertures in the supporting frame 3. Afterthe burner plate has been heated to a suitable temperature, the watermay be supplied to the burner plate as aforesaid and the air draftincreased in accordance with requirements. It is to be understood thatvarious alterations, modifications and/or additions may be introduced inthe foregoing construction and arrangement of parts without departingfrom thescope of the invention as defined by the appended claims.

Having now described my invention what I claim as new and desire tosecure by Letters Patent isr-- 1. A liquid fuel furnace comprising aninclined burner plate adapted to be heated and provided upon its uppersurface with a plurality of upstanding spaced projections, a pluralityof deflectors arranged over the burner plate in spaced `relationrelative to the flow direction of the fuel on the plate for causing aplurality of air drafts to be directed against different areas on thetop of the burner plate of which one deflector terminates in closeproximity to the projections to create a restricted passage for the airdraft located adjacent to said projections whereby the liquid fuel andthe air draft are forced to pass between said projections and are thusdivided into 'a number of relatively small streams which facilitatesvaporization of the fuel and mixing of the air draft and fuel vapour.V

2. A liquid fuel furnace according to claim 1, 1n which the burner plateincludes a relatively fiat section and said upstanding projections beingarranged in at least one row adjacent to the lower or rear edge of saidflat section, and in which each projection has in plan a convex frontedge merging into converging side walls which terminate at the rear in arelatively thin tail.

3. A liquid fuel furnace comprising an inclined burner plate adapted tobe heated and provided upon its'upper surface with a plurality ofupstandingspaced projections, means providing a restricted passage oroutlet located adjacent to said projections comprising at least one hoodpositioned above said burner plate and extending downwarly andrearwardly thereover, said hood being provided with at leat one airinlet opening through which an induced air draft is admitted to saidhood which is adapted to direct said air draft downwardly towards theburner plate and over the top thereof in close proximity thereto beforepassing through said restricted outlet whereby liquid fuel and the airdraft are forced to pass between said projections and are thus dividedinto a number of relatively small streams which facilitates vaporizationof the fuel and mixing of the air draft and fuel vapour, and at leastone internal partitionfor dividing the air draft passing beneath saidhood into a number of separate air streams and directing such airstreams downwardly towards different areas of the burner plate.

4. A liquid fuel furnace according to claim 3, in which an air inletfunnel is provided below the level of the inlet to said hood and isadapted to direct a draft of air straight across the burner plate inclose proximity to the upper surface thereof, and in which adjustableclosures are provided for the inlet openings associated with said hoodto vary the effective area thereof.

5. A device according to claim l, in which means are provided fordischarging relatively small streams of water ontothe heated burnerplate in advance of said restricted passage, said water supply meansincluding a series of delivery pipes, the lower ends of which arelaterally spaced above said burner plate and said delivery pipescommunicating at their upper ends with a cup adapted to receive thewater and having means for dividing the water into a number of streamswhich pass to the respective delivery pipes.

6. A device according to claim 1, in which the burner plate is providedWith a stepped portion at the lower end of the plate, the upper surfaceof said stepped portion being inclined in the opposite direction to thatof the main section of the burner plate and said main section beingprovided with an extension overhanging an upright wall of the steppedportion.

7. A device according to claim l, in which the burner plate is providedwith a stepped portion at the lower end of the plate, the upper surfaceof said stepped portion being inclined in the opposite direction to thatof the main section of the burner plate and said main section beingprovided with an extension overhanging an upwith a serrated edge.

SYDNEY HAROLD HOOK.

